1. Field of the Invention
The invention relates to the packaging and handling of sensitive components of the electronics industry and in particular to fragile dicing blades. Diamond, cubic boron nitride, amber boron nitride and silicon carbide blades are used for the cutting of hard brittle materials such as those used in the manufacture of microelectronic circuits and optical lenses that require small cutting blade widths. The invention addresses the handling, packaging, and storing of these fragile dicing blades and sensitive electronic components.
2. Background Art
The manufacturing of diamond dicing blades used by the electronics industry is done by a handful of producers. To date, there are no established standards regarding size, tolerance or labeling, and by no means is there an established form of packaging for these fragile dicing blades.
The dicing blade is a relative of the abrasive grinding wheel used by most machine shops and industrial manufacturers and the basis by which these tools work is similar. A major difference between these wheels or blades is the physical size. While there are many abrasive wheel manufacturers, they do not have the ability to manufacture such a fragile and delicate blade which is a reason for so few dicing blade manufacturers.
It is this handful of manufacturers that determines the packaging design for the dicing blade based on feedback from their customers and the experience gained through the trials, errors and testing of various packaging, handling and storing techniques. The result is that there are a variety of packaging designs presently used. Each manufacturer uses a different design than their counterpart. Each manufacturer has its advantages and disadvantages in present packaging design but certainly, no standard or consistency has been established as of this writing.
As discussed, precision abrasive dicing blades are basically abrasive wheels used for grinding, slotting, and cut-off operations very common in the machine shop environment but for major exceptions such as brittleness and size. Dicing blades range in blade thickness from as little as two ten thousandths of an inch (0.0002") to as high as one quarter of an inch (0.2500"). Diameters range, typically, from two to five inches. The finer thicknesses of 0.0008" to 0.0250" are extremely fragile and demand great care in packaging and handling in order to prevent breakage of the dicing blade. They are often broken during the handling of the blade prior to and following their use on the dicing saw or cutting machine. Improper handling during shipping, installation, and reuse results in broken, and thus unusable dicing blades.
Dicing blades are presently packaged and shipped in a variety of ways including rigid plastic or glass containers of various forms. In one example, of the rigid plastic container, a dicing blade or several dicing blades are sandwiched between layers of foam, placed within the container and sealed with a plastic cover which is taped to prevent accidental opening during handling and shipping. Identifying labels are generally affixed to the plastic cover, or lid. In this type of packaging, care must be taken to avoid pressing down on the top layer of foam during removal. Pressing down on the top foam can cause breakage of the dicing blade.
In certain dicing blade package designs, the blade is placed onto a bottom rigid plastic or cardboard base having a raised center hub similar to a phonograph record resting on a turntable. The base is then placed into a box or container for further protection of the dicing blade. This bottom center hub is often a part of the package made of rigid plastic material which is then affixed with a mating top cover. These packages take many stages and are generally awkward to handle. Other packages have bottom sections that have depressions to fit both the inner and outer diameter of the dicing blade to prevent shifting during handling and transit. In certain similar embodiments, the hub or depression is made a part of the container.
Consequently, packaging these fragile dicing blades has been difficult and users continue to demand support from the blade manufacturers for improvements. Many packages utilize a flexible foam material to create an intimate contact with the dicing blade to prevent shifting within the container. Other packaging such as those made by vacuum formed plastics with top and bottom mating sections have raised hubs which rest on the topmost dicing blade and adjust to the height of the dicing blade or stacked blades. Many dicing blades are placed between two plates of glass or plastic held together with tape. Extreme care must be taken so that the dicing blade does not slide toward the tapes and adhere to the tape resulting in blade breakage upon opening this type of packaging.
U.S. Pat. No. 4,819,412 issued to Sengewald discloses a process for the manufacture of packages made of prefabricated containers which are substantially dimensionally stable and have at a filling end and an outwardly projecting flange edge on which a cover sheet is fixed by welding, hot sealing or bonding. A thermoplastic sheet is applied to the containers to register a cover with the cover being separated along weakening lines to form closed containers. The object of the invention was to facilitate packaging cups of thermoplastic sheet material closed by a cover sheet. Problems have occurred with similar packages when used with the fragile blades during the abrupt movements needed for dislodging the cover from the container.
U.S. Pat. No. 4,037,716 issued to Marks discloses a card holder for keys or similar items comprised of a thin card having a depressed region therein for receiving and containing the items and a pressure resealable, a partially adhesively-coated lid covers the depressed region and is stripped or peeled back to expose the contained items. The presence of the adhesive creates further problems for the fragile disk for even slight contact with the adhesive will cause the blade to fracture and become unusable.
U.S. Pat. No. 3,738,903 issued to Berwick et al. discloses an apertured article of manufacture sealed in a plastic film envelope both along the periphery and the edge of an aperture of the article. Opposite faces of the envelope, normally unconnected in the area of the aperture, are brought together and heat sealed. The method of hermetically sealing opposite faces of a plastic film envelope along the edge of an aperture includes clamping and heat sealing the edges. Focus in on protectively enclosing articles of manufacturer usually of a generally flat configuration in such a fashion as to leave the apertures open while at the same time sealing not only about the outer periphery of the article but also along the edge of the aperture itself. The very permanent nature of the sealing process dictates that once the package is opened, it can no longer be used as originally intended. It is important in the handling and storing of fragile blades that a package provide protection of the blade but also that it be usable to meet blade use demands.
U.S. Pat. No. 3,456,784 issued to Sirago discloses a rigid, fluid tight, hand fracturable container for protecting o-rings and other small rubber or synthetic plastic parts from deterioration and deformation. The patent discloses a container in which a chamber is defined between two panels which are sealed to one another in a fluid tight relationship. The container of the invention is adapted to protect a variety of sizes of circular precision seals from abrasion, deformation and deterioration through contact with the ambient atmosphere. Access to the stored material is achieved by fracturing the container thus permitting exposure and access. Again, reuse is not possible as is the case in many of the packages in the prior art.
U.S. Pat. No. 4,741,119 issued to Baryla discloses a display board for displaying a sheet document behind a transparent window which relies on attraction caused by static electricity to hold the sheet document between a backing board and the transparent window. Baryla '119 discloses the use of a backing board made of dielectric material which may be any synthetic resin having a high dielectric constant. As described, preferably the board is a relatively thick and rigid plate of acrylic resin having a smooth face for covering with a sheet of transparent plastic film. Baryla '119 further discloses that it is sufficient to rub the surface of the sheet document to charge it electrostatically such that it clings to the face of the backing board, and the cover sheet of transparent plastic is caused to cling electrostatically to the surface of the paper document, and cling in most instances, to marginal surface portions of the backing board. Although such a device and method is useful for displaying a sheet document, such in not the case for a fragile dicing blade. Fragile dicing blades are typically conductive. Static clinging of the conductive blade is therefore not possible as might be suggestive in the display device of Baryla '119. Further, the clinging forces developed by the static charges are typically orders of magnitude below what is required to hold items such as a fragile dicing blade in place. A clinging force unavailable through static cling is needed for a package needed in the industry. The teachings in the display of paper sheet documents using static cling techniques is not where one would look to solve the problems associated with the handling, packaging, and storing of fragile dicing blades.
Further, the teachings in the display arts in general do not solve the specific problems associated with handling the fragile blades. By way of example, U.S. Pat. No. 3,670,434 to Shibata et al. discloses an adhesive sheet device for mounting photographs and other display items in albums which includes providing a relatively thick backing sheet and thin film of pressure-sensitive adhesive coating on one surface of the sheet. A cover sheet is disengageably adhered to the coated surface of the backing sheet for insertion of an item beneath the cover sheet for clear viewing. As described earlier, the adhesive material would be harmful to the blade and cause breakage during use.